Pen cartridge



Aug-15,1957 R.M.JENKINS' 3,335,706

PEN CARTRIDGE 'F iled Aug 50, 1965 1 2 Sheets$heet 1 Roy M. Jenkins,

INVENTOR.

Golove 8 Kleinberg,

ATTORNEYS.

I Aug.'l5 1967 v MqENKINS 3,335,106

PEN CARTRIDGE Filed Aug. 50, 1965 I I i 2 Sheets-Sheet .j:

Roy M. Jenkins,

INVENTOR.

Golove 8 Kleinberg ATTORNEYS.

United States Patent 3,335,706 PEN CARTRIDGE Roy M. Jenkins, Burbank, Calif., assiguor to Lindy Pen Company Incorporated, North Hollywood, Calif. Filed Aug. 30, 1965, Ser. No. 483,417 5 Claims. (Cl. 120-42.4)

The present invention relates to filler tubes for writing instruments and more particularly to an improved method and apparatus for venting filler tubes, suitable for use with ball point writing instruments.

In writing instruments of the prior art utilizing a liquid ink for making the mark, and more particularly, ball point writing instruments which utilize a viscous writing fluid, ink supply reservoirs or filler tubes have been of two basic types. The first would include the capillary reservoirs in which the interior diameter of the filler tube was the largest size compatible with retention of capillary properties of the writing fluid to be used. Under normal circumstances, the capillary forces on the writing fluid in the interior of the reservoir is such that the ink will not flow from the open end of the reservoir, despite the orientation of the pen with respect to gravity. The second type is the over sized filler in which the ink can flow, and in which a follower or plug is necessary to prevent the ink from flowing out when the filler is inverted.

In all ball point pen writing instruments, there is an ever present need to provide a supply of air to replace the volume of ink used in writing operations. In many instruments, a vent to atmosphere is provided by an aperture either in the rear end, or in the barrel of the writing instrument, at a chosen location between the point and the rear end of the pen.

In one particular form of ball point writing instrument, which has achieved considerable popularity and commercial success over the years, the pen comprises a plastic barrel, into which is inserted the ink cartridge and point assembly. A button is provided at the opposite end of the barrel to finish the structure. In such a writing instrument, venting can be provided by perforating the button, providing a small hole in the barrel or by permitting loose fit of the point assembly at the barrel opening to enable suflicient leakage of air to accomplish the ventingpurpose.

The provision of a vent in the button frequently creates problems. The habits of many users include the placing of the pen in the month which frequently results in an expulsion or leakage of ink from the reservoir and which ulti mately leaks ink out of the writing instrument through the aperture to stain the users hand, clothing or lips. Other perforation or apertures in the barrel get clogged with lint and dirt and lose their utility. The provision of adequate venting without resulting in leakage, in view of user habits, has long been a problem in producing a satisfactory socalled nonrefillable, throw away pen, of the nonretracting type. One satisfactory approach to the problem has been the utilization of a metal filler tube of capillary dimensions having an outside diameter less than the inner diameter of the plastic barrel section. The tube is crimped to hold the filler in place by a frictional, swaging action. In such an instrument, clearance is provided between the point assembly of the cartridge and the point portion of the barrel, which allows venting to take place.

In recent years, however, it has been found desirable, both from a cost and aproduction standpoint, to use materials other than metal for ink cartridges. However, the use of such non-metalilc cartridges precludes the provision of suitable anchoring crimps in the cartridge which previously held the cartridge in place in the barrel. Accordingly, it is necessary to provide some type of tight fit to assure retention of the cartridge within the pen without movement at the point end. If a tight press fit is utilice ized beween the point assembly and the barrel, venting either in the barrel or near the button, must be provided. As pointed out above, apertures have been found undesirable.

According to the present invention, a plastic ink cartridge is provided, having one or more grooves on the outside surface. These grooves can be conveniently made at the time of the initial fabrication of the cartridge. The grooves permit a tight, frictional press-fit of the point assembly at the nose piece of the barrel of the pen to provide full support for the point assembly. At the same time, adequate venting takes place through the nose piece, without the need for any other vent orfice in the pen structure.

In a preferred embodiment of the invention, four longitudinal grooves are equally spaced about the circumference of the tube and extend the entire length of the tube. Alternatively, a fewer or greater number of grooves can be provided. If more grooves are provided, each is preferably shallow, to avoid undue weakening of the filler tube at the point of insertion of the point assembly.

While the preferred embodiments teach the provision of a groove that extends the length of the tube, as being most consistent with mass production, extrusion techniques, for the fabrication of the tubes, it is also within the invention to provide shorter grooves that extend for a portion only of the length. The length of the grooves is determined by the length of the inner surface of the barrel that is in intimate physical contact with the tube. This embodiment would be useful in combination with moulded pen barrels which have an internal taper portion converging toward the nose or front of the barrel to facilitate useful release. Since it is only necessary to provide a vent past the area of tight, press lit, the grooves need only extend to a point where the barrel internal diameter is nominally larger than the external diameter of the tube. However, if an extruded barrel is utilized in which the internal diameter of the barrel is uniform throughout, it is necessary to extend the grooves throughout the entire length of the filler tube, as in the preferred embodiment.

Yet other embodiments are provided in which a plurality of scratches or striations are provided on the outer surface of the cartridge or filler tube. Such surface modifications do not cause any material weakening of the tube. A flow of air is permitted between the filler and the internal surface of the barrel, while, at the same time, a tight frictional fit of the cartridge and point assembly is accomplished. Preferably, these striations or scratches can be provided during one of the steps in the original, initial fabricating process for the tube.

Still other embodiments of the present invention include the provision of one or more flat surfaces on an otherwise cylindrical filler tube which is adopted to fit into a circular orifice. As with the other embodiments, the flat surfaces need only extend through the areas of close frictional fit to provide a vent passage between the atmosphere and the reservoir portion of the filler tube.

Accordingly, it is an object of the present invention to provide an improved filler tube for ball point writing instruments, which provides an improved venting from the ink reservoir to the exterior of the pen.

It is yet another object of the invention to provide an improved plastic ink cartridge for ball point pens which can be tightly press fitted into the pen barrel and which permits venting from the interior of the pen to the exterior.

It is yet an additional object of the invention to provide an improved cartridge for a ball point pen which enables venting along the exterior surface of the cartridge.

It is yet an additional object of the invention to provide an improved ball point pen having a cartridge supported at both ends, which provides adequate venting adjacent the point assembly at the nose of the pen, creating an air passage from the interior of the cartridge and the exterior of the pen.

It is a further object of the invention to provide an improved plastic filler tube for ball point writing instruments which can be supported within the barrel and yet which permits ventilation of the ink reservoir.

It is yet still a further object of the invention to provide an improved plastic cartridge having venting means on the exterior surface of the cartridge which permits air communication between the interior of the cartridge and the exterior of the pen.

It is yet another object of the invention to provide an improved plastic ink cartridge for ball point pens which fits tightly within the barrel of the ball point pens but yet permit a flow of air intermediate the exterior of the cartridge and the interior of the pen barrel.

The novel features which are believed to be characteristic of the invention, both as to organization and method of operation, together with further objects and advantages thereof will be better understood from the following description considered in connection with the accompanying drawings in which several preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.

FIG. 1 is a perspective view of a typical non-refillable nonretractable ball point writing instrument of the prior art;

FIG. 2 is a side sectional view of a prior art writing instrument;

FIG. 3 is a side view, in greater detail of an improved filler tube according to the present invention;

FIG. 4 is a section view of the tube of FIG. 3, taken along a line 44 in the direction of the appended arrows;

FIG. 5 is a side view of yet another embodiment of the filler tube of the present invention;

FIG. 6 is a side section view of an improved nonretractable, nonrefillable ball point writing instrument including a molded barrel portion;

FIG. 7 is a sectional view of the pen of FIG. 6, taken along line 77 in the direction of the appended arrows;

FIG. 8 is a sectional view of the pen of FIG. 6, taken along line 88 in the direction of the appended arrows;

FIG. 9 is a portion of the side view of a different embodiment of a nonretractable, nonrefillable ball point writing instrument, including an extruded barrel member;

FIG. 10 is a side sectional view of the pen of FIG. 9, taken along a line 10-10 in the direction of the appended arrows; and

FIG. 11 is a cross section view of an alternative embodiment of the present invention showing a filler tube employing flats on the exterior surface rather than grooves.

Turning first to FIG. 1, there is shown a conventional nonrefillable, nonretractable ball point pen 10, according to the prior art which includes a point assembly 12, a barrel portion 14, and a protective button 16. Although not shown herein, a conventional cap member is used to protect the point assembly when not in use and a clip is provided with which the pen can be held in a pocket.

In FIG. 2, there is shown in section, in addition to the point assembly 12, barrel 14 and button 16, an ink cartridge or filler tube which, in the prior art pens of metal and includes crimps 22 which enable a force fit with the interior of the barrel 14.

As shown, the point assembly 12, is tightly wedged into the inner diameter of the filler tube 20, and the filler tube 20 itself, is wedged by deforming the interior of the barrel 14, with crimps 22. The button 16 is provided with internal cylindrical section 24 which fits snugly against the interior walls of the barrel and includes a central hollow opening into which the filler tube abuts. This cylindrical portion 24 of the button 16 provides additional stabilizing support for the filler tube 2% when fitted into place in the barrel 14.

The combination of the frictional grip on the crimps 22 by the barrel 14, and the engagement of the cylinder section 24 of the button 16 with the rear end of the barrel 14 provides a two point stable suspension with which to hold the point 12 in place without wobbling while in use. The crimps 22 permit an air flow through the nose of the barrel.

In FIG. 3, a side view, partly in perspective, of a filler tube 20, according to the present invention shows in detail, the four vent grooves 122. In the embodiment shown in FIGS. 3 and 4, the grooves 122 extend the entire length of the filler tube 120. The interior of the filler tube 120 is of a dimension which may be considered capillary for the particular writing fluid or ink utilized, in the instrument. As seen in FIG. 3, a point assembly 112 is force fitted into one end of the plastic filler tube 120. When the filler tube 120 is force fitted into the plastic barrel 114, as shown in FIG. 6, the point assembly 112 is wedged into place, even more tightly.

The grooves 122 are made in the outer periphery of the filler tube 120, as shown in FIG. 4. It has been found experimentally, that the depth of a groove 122 can be rather critical. If too deep, an undue strain may be placed on the plastic when the point assembly is inserted and the tube can split or crack. If too shallow, the plastic may flow and block off the opening provided by the grooves. With the plastics most commonly used for pen cartridges, the depth should not exceed 15% of the wall thickness. The width of the groove 122 at the outer surface, can, however, be as much as twice the depth of the groove or more.

The groove 122 need not be circular, and can, in cross section, be any curve. Curves are preferable, to straight sided cuts, since any sharp groove may also introduce weak spots in the plastic, which, under stress or strain, may give way. However, it has also been found, experimentally, that lesser widths and depths are permissible and, may even comprise a series of shallow scratches or striations, so long as weak spots are not introduced.

An alternative groove arrangement is shown in FIG. 5, which illustrates a diiferent cartridge or filler tube 130 having a plurality of grooves 132. In this embodiment, the grooves 132 may be relatively shallow so long as sufiicient air can bypass the nose of the barrel and that the cold flow properties of the plastic wont close off all of the grooves 132.

Turning next to FIG. 6, there is shown in side sectional view a pen assembly using a filler tube according to the present invention. In this embodiment, a barrel 114 is initially manufactured by molding or casting. In such a case, an internal taper is provided to facilitate the release of the barrel from the fabricating mold.

Since the taper flares from the nose or tip 115 toward the rear, only a limited portion of the interior surface of the barrel is in intimate contact with the filler tube and accordingly, the grooves 122 or striations need not run the entire length of the cartridge, although in the preferred embodiment, they do.

As shown in FIGS. 6, 7 and 8, the grooves 122 extend the length of the barrel. A button 116 includes a relieved fiat area 117, which normally permits a flow of air between the inner portion of the barrel 114 and the interior of the filler tube 120. The grooves 122, however, provide still additional air passages between the interior or" the tube 120 and the interior of the barrel 114.

FIG. 7 is a sectional view showing the barrel 114, the filler tube 120, the grooves 122 and a writing fluid contained within the cartridge. In FIG. 8, the view, taken along the lines 88 of FIG. 6, there is shown the bar- =rel 114, an air gap, the cartridge 120 and the ink supplied therein.

In FIGS. 9 and 10 there is shown still another pen 130 in which the barrel 124 is produced by an extrusiontype process which results in a substantially uniform interior dimension. In such an embodiment, the filler tube 130 of FIG. 5, can be utilized and, as indicated by the cross section view of FIG. 10, includes a plurality of grooves 132 which run the length of the filler tube 29.

FIG. 11 shows yet another embodiment in which the grooves of a filler tube 144 are replaced by flats 146.

As shown, the flat 146 need not be wide and yet provides a vent to the interior of a pen barrel 140. It is understood that the opening in the nose of the barrel 140 is substantially circular and that any non-circular filler tube can be press fitted for stability, in the absence of cold flow of the plastic filler tube material, will enable the passage of air to the interior of the pen.

Thus there has been shown an improved filler tube or ink cartridge for use in ball point pens which is susceptible to high speed production methods and which permits venting from the atmosphere to the ink supply without the need for special vents, orifices or other additions to the pen barrel structure. By employing the vents of the present invention, a press fit of the point portion of the cartridge in the nose of the barrel can be employed to impart rigidity to the point assembly, without starving or otherwise restricting the flow of air to he carridge to replenish the volume of the ink removed by writing.

What is claimed as new is:

1. A ball point writing instrument comprising: a hollow barrel, an end button disposed in one end of the barrel, a point assembly, and a hollow cylinder containing a writing fluid; said cylinder having a constant outer diameter along its length and having integrally formed venting means including a relieved portion in the outer surface of said cylinder extending longitudinally along its entire length, said cylinder frictionally retaining the point assembly inside the cylinder at one end thereof, said cylinder being retained inside the barrel by frictional engagement of the outer surface of the cylinder with the inside surface of the barrel and by supported engagement with the end button disposed at the other end of the barrel, whereby said relieved portion in the surface of the cylinder vents the interior of said cylinder through the engagement with the end button, and through the frictional retention at one end of the barrel to the exterior of the barrel.

2. Ball point writing instrument filler means as in claim 1, wherein said cylinder is a plastic material.

3. Ball point writing instrument filler means as in claim 1, wherein said venting means includes a plurality of relieved portions, each being a longitudinal groove extending the entire length of said cylinder.

4. Ball point writing instrument filler means as in claim 1, wherein said relieved portion is a fiat surface.

5. In the writing instrument of claim 1, wherein said venting means relieved portion is a striation in the surface of said cylinder, and wherein said venting means further include a plurality of said striations.

References Cited FOREIGN PATENTS 1,157,099 12/1957 France. 1,191,422 4/1959 France. 1,202,449 7/ 1959 France. 1,033,092 6/1958 Germany.

782,159 9/ 1957 Great Britain.

LAWRENCE CHARLES. Primary Examiner. 

1. A BALL JOINT WRITING INSTRUMENT COMPRISING: A HOLLOW BARREL, AND END BUTTON DISPOSED IN ONE END OF THE BARREL, A POINT ASSEMBLY, AND A HOLLOW CYLINDER CONTAINING A WRITING FLUID; SAID CYLINDER HAVING A CONSTANT OUTER DIAMETER ALONG ITS LENGTH AND HAVING INTEGRALLY FORMED VENTING MEANS INCLUDING A RELIEVED PORTION IN THE OUTER SURFACE OF SAID CYLINDER EXTENDING LONGITUDINALLY ALONG ITS ENTIRE LENGTH, SAID CYLINDER FRICTIONALLY RETAINING THE POINT ASSEMBLY INSIDE THE CYLINDER AT ONE END THEREOF, SAID CYLINDER BEING RETAINED INSIDE BARREL BY FRICTIONAL ENGAGEMENT OF THE OUTER SURFACE OF THE CYLINDER WITH THE INSIDE SURFACE OF THE BARREL AND BY SUPPORTED ENGAGEMENT WITH THE END BUTTON DISPOSED AT THE OTHER END OF THE BARREL, WHEREBY SAID RELIEVED PORTION IN THE SURFACE OF THE CYLINDER VENTS THE INTERIOR OF SAID CYLINDER THROUGH THE ENGAGEMENT WITH THE END BUTTON, AND THROUGH THE FRICTIONAL RETENTION AT ONE END OF THE BARREL TO THE EXTERIOR OF THE BARREL. 